Equipment Reliability

Reliability and availability are two of the most important, and often confused, maintenance KPIs. The difference is crucial:

What reliability measures

• Reliability is about how infrequently a machine fails. It's a measure of failure frequency. A highly reliable vehicle is one that rarely breaks down.
• Availability is about whether the machine is ready to work when you need it. It's a measure of uptime.

You can have an unreliable machine with high availability if its failures are very minor and repairs are extremely fast. Conversely, you could have a very reliable machine that rarely fails, but when it does, the repair takes weeks, resulting in poor availability.

How it is quantified

Reliability is commonly measured by Mean Time Between Failures (MTBF). A higher MTBF means the equipment is more reliable. Improving reliability is a primary goal of preventive and predictive maintenance strategies. By preventing failures from occurring in the first place, you directly increase the reliability of the equipment, which in turn is a major driver of increased availability.